SUMMARY OBJECTIVE: To define 24-h characteristics of arterial blood pressure in healthy adolescent girls and boys; to determine gender-related differences of blood pressure, its circadian pattern.MATERIAL AND METHODS: The 24-h blood pressure was monitored hourly in healthy girls (n=22, without no account for the menstrual cycle phase) and boys (n=22). Additionally, blood pressure of adolescent girls (n=15) was examined during different phases of their menstrual cycle (follicular, ovulation, and luteal). Blood pressure was monitored with an auto-cuff automatic outpatient blood pressure monitor.RESULTS: Investigation showed gender-related differences in 24-h blood pressure. Study results revealed the circadian blood pressure rhythm characterized by a period of low values during nighttime and an early morning increase in both adolescent groups. Nocturnal systolic blood pressure was higher (P<0.05) in boys than in girls in all phases of their menstrual cycle. Diurnal systolic blood pressure in boys was higher than in girls in their follicular phase (P<0.05). The day and night blood pressure differed between boys and girls (P<0.05). A dipping blood pressure pattern as a decrease in mean nighttime blood pressure as compared with mean daytime blood pressure was defined: 10.02+/-6.7% in girls (n=22) and 13+/-6.3% in boys (n=22), without gender-related differences (P>0.05). There were no differences in blood pressure dipping among girls' groups in different menstrual cycle phases (P>0.05). Adolescent boys showed a significant positive correlation between their mean diurnal blood pressure and height (P<0.05).CONCLUSION: The study proved gender-related arterial blood pressure differences in healthy adolescents. The results demonstrate the gender-specific circadian blood pressure rhythm pattern in both gender groups.